Method for producing profile sealing rings

ABSTRACT

A method for producing profile sealing rings, in particular in a C-, V-, or U-shape, in which a profile strand ( 24 ) of definable cross-sectional shape is obtained from a band-shaped carrier part ( 2 ) by forming and the use of forming rolls ( 14, 16, 20, 22 ), the process of forming proceeding such that the profile strand ( 24 ) assumes at least part of an arc shape or spiral shape after forming.

The invention relates to a method for producing profile sealing rings, in particular in a C-, V-, or U-shape.

Profile sealing rings are widely used as a component of seal arrangements, in junction connections of exhaust gas-carrying lines, for example, for connections of lines to catalytic converters or cylinder heads of internal combustion engines, or for other components which carry hot gas, such as are generally found in power plant engineering. Due to the high exhaust gas temperatures which occur, the respective profile sealing ring is generally a metal component with a small wall thickness, the ring body conventionally having a profiled cross-sectional shape, for example in the form of a C-, U-, or V-profile.

According to the prior art shown in document EP 2 020 541 A1, in the production of these profile sealing rings from a sheet metal strip, a ring is formed after the sheet metal strip has been cut to the length of the periphery of the ring; then the ends of the strips are welded to form a closed ring, and it is profiled by rolling.

Proceeding from this prior art, the object of the invention is to make available a method which enables especially efficient production.

This object is achieved according to the invention by a method having the features of claim 1 in its entirety.

Accordingly, one important particular of the invention is that a band-shaped carrier part is formed by means of forming rolls such that not only is a profile strand of predetermined cross-sectional shape formed, i.e., with a C-, V-, or U-shaped cross section, but that the profile strand, after forming, is curved in the shape of an arc or spiral. The process of profiling thus also includes the formation of the curvature of the strand into the desired ring shape, so that a separate bending process for ring formation is eliminated. The method according to the invention therefore enables especially economical production of profile sealing rings at a high production rate.

Because the profile strand is already in an arc shape, sections of a length having a length which corresponds to the periphery of the respective profile ring to be formed can be easily connected, in particular by welding.

The method can be carried out especially advantageously such that the profile strand is formed from the carrier part which moves in the lengthwise direction in several forming stages, the forming rolls which form the last forming singe on the facing surfaces of the profile strands causing varied friction and/or deformation in order to produce the arc-shaped or spiral curvature of the profile strand which emerges from this forming stage.

Preferably, the flat carrier part is supplied by means of conveyor rollers to the first forming stage, in which the first forming roll with a convexly raised jacket part and an opposite second forming roll with a concavely depressed jacket part shape the carrier part into the preformed profile strand.

Preferably, the arrangement is such that at least one forming roll of the two forming stages can be adjusted both in the working direction and also transversely to the working direction. In this way a different material thickness can be implemented in the preformed profile strand in different wall regions of the profile shape. Thus, for example, in the region of the back of a formed C- or U-profile, a greater wall thickness than on the lateral legs can be formed; this leads to optimum strength and elasticity conditions for the finished profile sealing ring.

Preferably, the preformed profile strand of the last forming stage emerging from the first forming stage is supplied by way of guide rollers which can be adjusted transversely to the working direction.

In order to achieve the desired arc-shaped or spiral curvature of the strand which emerges from the last forming stage, preferably in the last forming stage which has a third forming roll with a convexly raised jacket part and a fourth forming roll with a concavely depressed jacket part, it is possible to proceed such that not only the final profile shape is obtained, but also that by adjusting the peripheral velocities and the forming pressure in the last forming stage the arc-shaped or spiral curvature of the emerging profile strand is formed.

One especially important advantage of the method according to the invention consists in that it is equally well-suited for production of profile sealing rings in which the profile opening is on the outside of the ring, as well as for profile sealing rings whose profile is opened into the interior of the ring. In this respect, according to the invention, it is possible to proceed such that the direction of the curvature is chosen in order to obtain as desired a profile strand with a profile which is opened to the inside or outside, relative to the arc shape, by the positioning and shaping of at least the fourth forming roll and setting of the peripheral speeds of at least one of the third and fourth forming rolls.

The invention is detailed below using the drawings.

FIG. 1 shows a highly schematically simplified representation of a device for carrying out one exemplary embodiment of the method according to the invention;

FIG. 2 shows a broken away and a highly schematically simplified cross section of the device from FIG. 1, according to the intersection line as indicated with II-II in FIG. 1, and

FIG. 3 shows a highly schematically simplified top view of the device from FIG. 1.

As FIGS. 1 and 3 show, the carrier part 2 is routed in the form of a flat steel band by feed rollers 4 through a first forming stage 6 and a second forming stage 8, the carrier part 2 being held in the middle by lateral guide rollers 10 and 12. In the first forming stage 6, the carrier part 2 is formed by means of a first forming roll 14 and a second forming roll 16 which interacts with it into a preformed profile strand 18 from which the final profile of the finished profile strand 24 emerging from the device is formed in the second forming stage 8 by means of a third forming roll 20 and a fourth forming roll 22 which interacts with it.

The guide rollers 10 and 12 can be positioned on carriers 26 transversely to the feed direction. In the first forming stage 6, the first forming roll 14 with the convexly raised jacket part 28 acts on the supplied carrier part 2 in the middle, see FIG. 2, while the second forming roll 16, which is the lower one in FIGS. 1 and 2, with the concavely depressed jacket part 30 deforms the carrier part 2 laterally toward the top in order to impart a cross-sectional shape in the form of a flat, widely opened C to the preformed profile strand 18 emerging from the first forming stage 6. While in the subsequent, second forming stage 8, the third forming roll 20 at the top in FIGS. 1 and 2 has a raised jacket part 32 which corresponds to the jacket part 28 of the first forming roll 14, the concavely depressed jacket part 34 of the fourth forming roll 22 is made much differently from the concavely depressed jacket part 30 of the second forming roll 16. In the exemplary embodiment described here, in which the finished profile strand 24 forms a comparatively narrow C-profile, the jacket part 34 of the forming roll 22 is made in the form of a narrower and more deeply machined depression, compared to the jacket part 30 of the forming roll 16. In this way a profile shape is imparted to the finished profile strand 24, as is schematically indicated in FIG. 1 at 36.

For the process of preprofiling in the first forming stage 6, in this example the second forming roll 16 can be positioned as indicated with the double arrow 38 in the direction to the upper forming roll 14 in order to reduce the size of the roll gap, and according to the double arrow 40, along the working direction. As indicated with the corresponding double arrows 38 and 40 in the second forming stage 8, the fourth forming roll 22 can be positioned accordingly in the direction to the pertinent forming roll 20 and along the working direction. In addition, the peripheral velocities of the forming rolls, at least the forming rolls 20 and 22 of the second forming stage 8, can be adjusted independently of one another. By setting these parameters, in the forming process in the second forming stage 8 action is applied to the material of the preformed profile strand 18 such that material stretching on the profile base is different relative to the stretching on the side parts of the profile. This leads to a curvature of the finished profile strand 24 so that it leaves the second forming stage 8 in an arc shape, see FIG. 1. When the finished strand 24 is routed toward the side by the positionable guide roller 42, the profile strand 24 forms loops 44 which are taken up in a spiral, see FIG. 3. For the final ring shape of the profile sealing ring, therefore only sections of length which correspond to the periphery of the profile sealing ring need be cut to length from the loops 44 and on the end side need be welded to form the finished profile sealing ring without a bending process being necessary on a straight profile strand.

The forming in the second forming stage 8 can take place especially advantageously such that the material of the profile strand 18 is less stretched on the profile base than on the profile sides. This can be brought about by stronger friction in the rolling process taking effect on the profile sides by the shape and dimensioning of the interacting jacket parts of the forming rolls 20 and 22, for example, by the depressed jacket part 34 being narrowed in the external region, so that the profile strand 24 in the outer region is more heavily stretched than in the profile base. In this way the finished profile strand 24, relative to the curvature shown in FIG. 1 with the solid line, emerges to the top with a curvature pointed downward from the second forming stage 8, as is shown in FIG. 1 with the broken line. As is indicated in FIG. 1 at 36, in both instances the profile is thus opened toward different sides. The invention thus makes it possible to easily produce profile sealing rings with a profile that is open in the desired direction.

Depending on the deformation of the convexly raised jacket parts of the forming rolls and the concavely depressed jacket parts of the mating roll which interact with them, profile shapes other than the illustrated C-shape can be implemented, and profile shapes can also be produced in which the side walls of the profile can be irregularly arced. Likewise, contouring can be impressed on the outer sides or inner sides. The production process can take place continuously by the carrier part 2 being withdrawn as an endless sheet metal strip from a supply and routed through the forming stages 6, 8 with the same working direction. Alternatively, defined lengths of the carrier part 2 can be moved by means of a linear advance device in repeated back-and-forth motion through the forming stages 6 and 8 in order to form the finished profile strand 24 in several roll steps, optionally with altered positioning of the forming rolls, especially of the rolls 16 and 22.

Preferably, it is also possible to obtain the illustrated profiled ring with only one pair of forming rolls 20, 22. Here the carrier part 2 is moved as a blank in a rocking process, i.e., by motion of the blank back-and-forth through the corresponding roll pair preferably into a closed ring shape. The blank at the start of the rolling process has a finite length which includes the required peripheral length of the ring. The blank is rolled into the round shape by the rocking motion of the blank in the lengthwise direction of the strip which is stretched during the forming process. The several rocking processes required for this purpose preferably are carried out continuously and therefore in succession in the manner of a multistep process up to final production. Then the ring is removed from the forming device, and on the end side it is brought, for example by a welding process, into the ring shape which remains closed. 

1. A method for producing profile sealing rings, in particular in a C-, V-, or U-shape, in which a profile strand (24) of definable cross-sectional shape is obtained from a band-shaped carrier part (2) by forming and use of forming rolls (14, 16, 20, 22), the process of forming proceeding such that the profile strand (24) assumes at least part of an arc shape or spiral shape after forming.
 2. The method according to claim 1, characterized in that sections of length of the profile strand (24), which is in an arc shape, are connected, in particular by welding, on the end side for forming the ring body of the profile sealing ring.
 3. The method according to claim 1 or 2, characterized in that the profile strand (24) is formed from the carrier part (2) which moves in the lengthwise direction in several forming stages (6, 8), the forming rolls (20, 22) which form the last forming stage (8) on the facing surfaces of the profile strands causing varied friction and/or deformation in order to produce the arc-shaped or spiral curvature of the profile strand (24) which emerges from this forming stage (8).
 4. The method according to claim 3, characterized in that the flat carrier part (2) is supplied by means of conveyor rollers (4) to the first forming stage (6) in which the first forming roll (14) with a convexly raised jacket part (28) and an opposite second forming roll (16) with a concavely depressed jacket part (30) shape the carrier part (2) into the preformed profile strand (18).
 5. The method according to claim 4, characterized in that at least one forming roll (14, 16, 20, 22) of the two forming stages (6, 8) can be adjusted in the working direction and transversely to the working direction to change the roll gap.
 6. The method according to claim 5, characterized in that the preformed profile strand (18) of the last forming stage (8) emerging from the first forming stage (6) is supplied by way of guide rollers (12) which can be adjusted transversely to the working direction.
 7. The method according to claim 6, characterized in that in the last forming stage (8) with a third forming roll (20) which has a convexly raised jacket part (32) and fourth forming roll (22) with a concavely depressed jacket part (34) the final profile shape is formed and by adjusting the peripheral velocities and the forming pressure in the last forming stage (8) the curvature of the emerging profile strand (24) is formed.
 8. The method according to claim 7, characterized in that the direction of curvature is chosen in order to obtain as desired a profile strand (24) with a profile which is opened to the inside or outside, relative to the arc shape, by shaping and positioning at least the fourth forming roll (22) and by setting the peripheral speed of at least one of the third (20) and fourth forming rolls (22).
 9. The method according to claim 1, characterized in that the profiled arc shape is formed from the band-shaped carrier part (2) by forming, using a pair of forming rolls (20, 22), in the manner of a rocking motion by continuous back-and-forth movement of the carrier part (2) along the pair of forming rolls (20, 22). 